oxygen toxicity


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ox·y·gen tox·ic·i·ty

1. a bodily disturbance resulting from breathing high partial pressures of oxygen; characterized by visual and hearing abnormalities, unusual fatigue while breathing, muscular twitching, anxiety, confusion, incoordination, and convulsions; can occur when excessive quantities of oxygen are administered in patients (such as during adult respiratory distress syndrome), resulting in worsening of pulmonary infiltrates and clinical deterioration; although the mechanism for development of the condition is obscure, a disruption of enzymatic activity is likely, perhaps as a result of free radical formation. Compare: retrolental fibroplasia.
2. exposure of the lungs to greater than 60% oxygen for periods exceeding 24-48 hours can lead to severe, irreversible pulmonary fibrosis.
Synonym(s): oxygen poisoning

oxygen toxicity

a condition of oxygen overdosage that can result in pathological tissue changes, such as retinopathy of prematurity or bronchopulmonary dysplasia. It can also decrease the hypoxic drive to breathe.
Microbiology The toxic effects of atmospheric O2 on strict anaerobic bacteria are not fully understood and may be related to the lack of enzymes—e.g., superoxide dismutase, catalases, and peroxidase—capable of metabolizing free radicals, and are incapable of growth in greater than 0.5% ambient O2; to reduce the oxidation-reduction or ‘redox’ potential of a medium, reducing agents such as thioglycolate and l-cysteine may be added to the anaerobic transport medium
Pulmonary medicine Tissue and molecular damage due to the effects of O2 free radicals in cellular and extracellular micro-environments; OT occurs in infants—retinopathy of prematurity—and in the elderly—shock and inflammation

oxygen toxicity

Tissue and molecular damage due to the effects of O2 free radicals in cellular and extracellular micro-environments; OT occurs in older subjects, shock and inflammation. See Oxygen radical.

ox·y·gen tox·ic·i·ty

(ok'si-jĕn tok-sis'i-tē)
A body disturbance resulting from breathing high partial pressures of oxygen; characterized by visual and hearing abnormalities, unusual fatigue while breathing, muscular twitching, anxiety, confusion, incoordination, and convulsions.

oxygen

a chemical element, atomic number 8, atomic weight 15.999, symbol O. See Table 6. It is a colorless and odorless gas that makes up about 20% of the atmosphere. In combination with hydrogen, it forms water; by weight, 90% of water is oxygen. It is the most abundant of all the elements of nature. Large quantities of it are distributed throughout the solid matter of the earth, because the gas combines readily with many other elements. With carbon and hydrogen, oxygen forms the chemical basis of much organic material. Oxygen is essential in sustaining all kinds of life.

oxygen analyzer
an instrument that measures the concentration of oxygen in a gas mixture.
oxygen deficiency
significant cause of losses in cultivated finfish in enclosed dams, but also in rivers and estuaries, caused by lack of natural aeration of the water or to heavy algal blooms, bushfire ash deposits and overcast conditions leading to respiration rather than photosynthesis or a high concentration of organic matter and leading to the development of a bacterial bloom; a high temperature exacerbates the development.
oxygen flux equation
a calculation that determines the rate at which oxygen is made available to tissues, based on cardiac output and arterial oxygen content.
oxygen-hemoglobin dissociation curve
a graphic explanation of the release and acquisition of oxygen from and to the hemoglobin in the blood in varying circumstances of oxygen partial pressure in the environment.
oxygen regulator
see reducing valve.
oxygen saturation
the amount of oxygen bound to hemoglobin in the blood expressed as a percentage of the maximal binding capacity.
oxygen saturation curve
graphical representation describing the relationship (usually curvilinear) between fraction of oxygen-binding sites (of a protein) that have oxygen bound to them and the partial pressure (concentration) of free oxygen.
oxygen tank
the heavy metal cylinder in which medical gases are compressed at high pressure. Called also oxygen cylinder.
oxygen tension
see tension (2).
oxygen tent
an enclosed space or plastic canopy used for oxygen therapy, humidity therapy or aerosol therapy.
oxygen therapy
supplemental oxygen administered for the purpose of relieving hypoxemia and preventing damage to the tissue cells as a result of oxygen lack (hypoxia). Companion animals are usually placed in a special cage with oxygen piped to it. A mask is used for short-term administration. Large animals can be supplied by a nasal tube taped in place to deliver oxygen into the pharynx.
oxygen toxicity
tissue damage may occur with exposure to high concentrations of oxygen for long periods. See also retrolental fibroplasia.
oxygen-transfer chain
a functional chain describing the transfer of oxygen from the external environment to the metabolizing tissue; includes uptake in the respiratory system, binding to hemoglobin, transport through the circulatory system, diffusion and dissociation in tissues and utilization in mitochondria, i.e. oxidatable substrates and enzymes.
oxygen transport
process of transfer of oxygen around the body either attached to hemoglobin or myoglobin.
References in periodicals archive ?
Historical introduction to the "free radical theory" of oxygen toxicity.
We believe this to be the first report of nitric oxide use in sparing further oxygen toxicity in bleomycin-treated patients.
The emetic episode of patient 2 during her first treatment could have been a premonitory sign of central nervous system (CNS) oxygen toxicity, since she was slightly febrile, which is known to be a predisposing factor to CNS oxygen toxicity.
One of them had pulmonary dissemination of the fungal infection, which may have rendered the lungs more susceptible to oxygen toxicity.
The visual side effects of oxygen toxicity are twitching of the eyelids and blurred vision.
The most common type of oxygen toxicity is lenticular or affecting the lens.
Another issue for divers today is oxygen toxicity, which I wrote about in the last issue of Focus.
There are two ways oxygen toxicity occurs as a result from over exposure; pulmonary oxygen toxicity and cerebral oxygen toxicity.